Kuang-Yi Tseng

Comparison of the GlideScope® videolaryngoscope and the Macintosh laryngoscope for double‐lumen tube intubation

Intubation with a double‐lumen tube is important for achieving one‐lung ventilation and facilitating thoracic surgery. The GlideScope® videolaryngoscope (Verathon Inc., Bothell, WA, USA) is designed to assist tracheal intubation for patients with a difficult airway. We wished to compare the GlideScope and direct laryngoscopy for double‐lumen tube intubation. Sixty adult patients requiring a double‐lumen tube for thoracic surgery and predicted uncomplicated laryngoscopy were randomly assigned to a direct Macintosh laryngoscopy group (n = 30) or a GlideScope group (n = 30). The mean (SD) duration of intubation was longer in the Macintosh group (62.5 (29.7) s) than in the GlideScope group (45.6 (10.7) s; p = 0.007). There was no difference in the success of the first attempt at intubation (26/30 (87%) and 30/30 (100%) for Macintosh and GlideScope groups, respectively; p = 0.112). The incidence of sore throat and hoarseness was higher in the Macintosh group (18 (60%) and 14 (47%), respectively) than in the GlideScope group (6 (20%) and 4 (13%), respectively; p = 0.003 and 0.004). We conclude that double‐lumen tube intubation in patients with predicted normal laryngoscopy is easier using the GlideScope videolaryngoscope than the Macintosh laryngoscope.

Electromyographic endotracheal tube placement during thyroid surgery in neuromonitoring of recurrent laryngeal nerve

Intraoperative neuromonitoring (IONM) is widely used in thyroid surgery. This study aimed to investigate the influence of neck extension on electromyographic (EMG) endotracheal tube displacement and to determine the necessity of routinely checking the final electrode position after the patient had been fully positioned. A consecutive 220 patients undergoing thyroidectomy were enrolled. All patients were intubated with the EMG endotracheal tube under direct laryngoscopy. The electrode position and tube displacement were routinely checked and measured by laryngofiberoscopy before and after patient positioning. The patients were divided into two groups. In Group I (n = 110), the EMG tube was taped and fixed to the right mouth angle before full neck extension. In Group II (n = 110), the EMG tube was disconnected from the circuit tube and was not taped until full neck extension. In all patients, we ensured that the final electrode position was the optimal position with laryngofiberoscopic examination. The tube displacement after neck extension ranged from 16 mm upward to 4 mm downward in Group I and from 12 mm upward to 5 mm downward in Group II. The rate of tube displacement greater than 10 mm was 12.7% in Group I and 3.6% in Group II. Successful monitoring was achieved in all patients after the final optimal position of electrodes was ensured routinely. The electrode position can be severely displaced after the patient has been fully positioned. Verification of ideal position of electrodes before the beginning of the operation is a necessary step to guarantee functional intraoperative neuromonitoring.

A comparative study between 1 and 2 effective doses of rocuronium for intraoperative neuromonitoring during thyroid surgery

BACKGROUND The goal of this study was to explore an ideal application of rocuronium to enable adequate muscle relaxation for intubation without significantly affecting the evoked potentials measured by intraoperative neuromonitoring during thyroid surgery. METHODS A total of 80 patients were randomized to receive 1 (group 1, n = 40) or 2 (group 2, n = 40) effective doses (ED(95)) of rocuronium to facilitate electromyographic (EMG) endotracheal tube insertion. Evoked potentials were obtained every 5 minutes by stimulating the vagus nerve between the time period of 30 and 70 minutes after administration of rocuronium. The magnitude of evoked potentials at each time point and the tracheal intubating conditions were compared between groups. Accelerometry (twitch [% TW]) was used to monitor the quantitative degree of neuromuscular transmission at the adductor pollicis muscle. RESULTS At 30 minutes after administration of rocuronium, the rate of positive EMG response was 100% (40/40) in group 1 and 53% (21/40) in group 2 (P < .001). Positive EMG signals were obtained for all patients in group 2 until 55 minutes after administration of rocuronium. The mean amplitude detected from the time point of 30 to 60 minutes was greater in group 1 than in group 2 (P < .01). The time to tracheal intubation was 208 ± 59 seconds in group 1 and 114 ± 26 seconds in group 2 (P < .001). The overall intubating conditions were better in group 2 than in group 1 patients (P < .001). CONCLUSION A total of 1 ED(95) of rocuronium (0.3 mg/kg) is an optimal dose for intraoperative neuromonitoring during thyroid surgery. Positive and high EMG signals were obtained in all patients at an early stage of operation, and satisfactory intubating conditions were achieved in most patients.

Left endobronchial intubation with a double‐lumen tube using direct laryngoscopy or the Trachway® video stylet

We compared direct laryngoscopy with a Macintosh blade vs indirect bronchoscopy with a Trachway® stylet, for endobronchial intubation with a left‐sided double‐lumen tube. We allocated participants scheduled for thoracic surgery and who had normal predicted laryngoscopy, 30 to each group. The mean (SD) intubation times with laryngoscope and Trachway were 48 (11) s vs 28 (4) s, respectively, p < 0.001. The rates of hoarseness on the first postoperative day, categorised as none/mild/moderate/severe, were 10/12/7/1 and 22/6/2/0, respectively, p = 0.008, without differences on subsequent days. Left endobronchial intubation with a double‐lumen tube is slower using direct laryngoscopy and causes more hoarseness than indirect bronchoscopy with a Trachway stylet.

Nasotracheal intubation in patients with limited mouth opening: a comparison between fibreoptic intubation and the Trachway®

In patients with limited mouth opening, traditional laryngoscopy and videolaryngoscopes are not useful when performing nasotracheal intubation. Eighty patients with limited mouth opening who required nasotracheal intubation were randomly assigned to either fibreoptic intubation (n = 40) or the Trachway® (n = 40). Using the modified nasal intubation difficulty scale, 22 (55%) patients who received fibreoptic intubation were categorised as no difficulty compared with 40 (100%) patients in the Trachway group (p < 0.001). Mean (SD) total intubation time was 71.8 (23.3) s in patients who received fibreoptic intubation compared with 35.4 (9.8) s in the Trachway group (p < 0.001). We conclude that the Trachway technique for nasotracheal intubation is quicker and easier compared with fibreoptic intubation in patients with limited mouth opening.

Reversal of rocuronium-induced neuromuscular blockade by sugammadex allows for optimization of neural monitoring of the recurrent laryngeal nerve

The use of neuromuscular blocking agent may effect intraoperative neuromonitoring (IONM) during thyroid surgery. An enhanced neuromuscular‐blockade (NMB) recovery protocol was investigated in a porcine model and subsequently clinically applied during human thyroid neural monitoring surgery.

A comparison of Trachway intubating stylet and Airway Scope for tracheal intubation by novice operators: A manikin study

The Trachway is a recently developed intubation device that resembles an illuminating stylet and incorporates a video‐assisted system. This study evaluated the use of this system for tracheal intubation by novice operators. This randomized cross‐over study compared the Trachway and the Airway Scope in simulated routine and difficult intubation scenarios. The difficult scenario was simulated by increasing the tongue volume of the manikin. The primary outcome measure in both airway scenarios was the time required for a successful tracheal intubation. For each scenario, the success rate, ease of intubation and operator preference were recorded for the two devices and compared. Average intubation time did not differ significantly between the Trachway and Airway Scope for the normal airway scenario (11.2 ± 6.5 vs. 9.8 ± 4.3 seconds, respectively; p = 0.07), but was significantly longer using the Trachway than with the Airway Scope on the difficult airway scenario (17.1 ± 11.1 vs. 9.5 ± 4.1 seconds, respectively; p < 0.001). The overall success rates of the Trachway and Airway Scope (96.3% and 98.6%, respectively) did not differ significantly (p = 0.13). Preference for the Airway Scope was greater in both scenarios, and particularly in the difficult airway scenario (p < 0.001). Although the devices are comparable in terms of ease of use and intubation time in normal scenarios, the ease of using the Airway Scope makes it more suitable for inexperienced operators in difficult intubation scenarios.

A comparison between succinylcholine and rocuronium on the recovery profile of the laryngeal muscles during intraoperative neuromonitoring of the recurrent laryngeal nerve: a prospective porcine model.

The use of succinylcholine and rocuronium are reportedly feasible during intraoperative neuromonitoring (IONM) of the recurrent laryngeal nerve (RLN) in thyroid surgery. This study aimed to investigate and compare the recovery profiles of succinylcholine and rocuronium on the laryngeal muscle during IONM of the RLN in a porcine model. Nine male Duroc‐Landrace piglets were anesthetized with thiamylal and underwent tracheal intubation without neuromuscular blocking agents (NMBAs). Needle electrodes were inserted into the vocalis muscles through the cricothyroid ligament. The RLN was exposed and stimulated. Electromyographic (EMG) signals were obtained before and after the intravenous administration of a NMBA. The EMG amplitudes were measured before and after (at 1‐minute intervals) the administration of the study drug until complete recovery. The study NMBA regimen included succinylcholine (1 mg/kg), low‐dose rocuronium (0.3 mg/kg), and standard dose rocuronium (0.6 mg/kg). The maximal neuromuscular blockade and 80% recovery (i.e., duration) of the control responses were recorded and analyzed. The 80% recovery of the control response for succinylcholine (1 mg/kg) was 19.7 ± 1.5 minutes; low‐dose rocuronium (0.3 mg/kg), 16.3 ± 2.5 minutes; and standard dose rocuronium (0.6 mg/kg), 29.3 ± 5.7 minutes. Succinylcholine (1 mg/kg) and low‐dose rocuronium (0.3 mg/kg) had significantly shorter durations than standard dose rocuronium (0.6 mg/kg). The EMG signal recovery returned to baseline within 30 minutes in the succinylcholine and low‐dose rocuronium groups, but it did not return to baseline until 1 hour after surgery in the rocuronium (0.6 mg/kg) group. In this study, succinylcholine (1 mg/kg) and low‐dose rocuronium (0.3 mg/kg) had favorable recovery profiles on the laryngeal muscle. It is recommended that low‐dose rocuronium may replace succinylcholine for the induction of general anesthesia during IONM of the RLN in thyroid surgery.

Dose-dependent attenuation of intravenous nalbuphine on epidural morphine-induced pruritus and analgesia after cesarean delivery

Epidural morphine in patient‐controlled analgesia regimens controls postoperative pain well but easily induces pruritus and other epidural morphine‐related side effects. With 90 pregnant American Society of Anesthesiologists physical status II females scheduled for elective cesarean delivery, the present study was designed to evaluate the efficacy and safety profile of patient‐controlled antipruritus (PCP) use of intravenous nalbuphine‐based regimens for attenuation of postoperative pruritus and related side effects in combination with epidural morphine patient‐controlled analgesia with regard to the quality of postoperative pain management. Patients were randomly assigned to two nalbuphine groups (5 μg/kg/hour, Group N5 or 10 μg/kg/hour, Group N10) and bolus dose of 1.6 μg/kg for PCP or the control (normal saline) group. Comparable visual analog scale scores for rest pain at each measured time interval among the three groups demonstrated that adequate pain relief was offered; however, the cumulative dose of nalbuphine administered to the patients in Group N10 attenuated the analgesic effect of epidural morphine in moving pain at POh24 only. Fewer episodes and milder severity of pruritus were observed in patients in Groups N5 and N10 at all postoperative time intervals. Epidural morphine provided good postoperative pain relief but with incommodious side effects. In addition, intravenous nalbuphine not only attenuated the incidence of pruritus but also decreased total morphine consumption. In conclusion, intravenous administration of low‐dose nalbuphine (5 μg/kg/hour) for PCP maintained analgesia produced by epidural morphine and offered low pruritus incidence.

Fibreoptic bronchoscopy to facilitate ProSeal laryngeal mask airway insertion in a patient with ankylosing spondylitis

A 51-year-old male patient (height 156.5 cm, weight 50.5 kg, ASA 3) with severe ankylosing spondylitis presented for inguinal herniorrhaphy. His cervical spine was fixed with maximum flexion and extension of < 5 . He also demonstrated limited mouth opening of 25 mm and a thyromental distance of 30 mm. The angle between his oral and pharyngeal axes was measured on his lateral cervical spine radiograph as 67 (Fig. 4). We induced general anaesthesia with propofol 3 mg.kg and lidocaine 1 mg.kg, but neither the introducer tool nor a finger sweep technique was successful in placing the ProSeal laryngeal mask airway (PLMA, LMA ProSeal, San Diego, CA, USA) correctly because of folding over of anterior part of the cuff. We then used a fibreoptic bronchoscope (Olympus LF-2, Shinjuku, Tokyo, Japan) to assist placement by inserting it through the drainage tube of the PLMA, thereby anchoring the PLMA in the mouth and enabling us to advance the device into the oesophagus under direct vision into a satisfactory position. The operation proceeded uneventfully without postoperative complications. A sniffing (oropharyngeal angle of 120 ) to neutral (90 ) position has been recommended to ease insertion of the classical laryngeal mask airway (LMA) [1, 2]. If the angle of the oropharyngeal axis is < 90 , the LMA is more likely to impact the nasopharyngeal vault with folding over of its cuff [3]. In our case, the PLMA cuff folded over in the oropharynx despite using the introducer tool and index finger techniques. Our patient’s laryngeal and pharyngeal tissues could not be viewed clearly because of limited space between his tongue base and soft palate. Only his oesophageal lumen could be identified. The traditional bougie-guided technique is difficult in a patient with limited mouth opening [4]. We believe that fibreoptic bronchoscopy in assisting PLMA placement has advantages over the blind techniques utilising a gum elastic bougie [5] or nasogastric tube because of the flexible tip of the bronchoscope and the use of direct vision to negotiate the sharp curve of the pharynx. This should help avoid unexpected trauma or accidental intratracheal placement. The Glidescope (Verathon Inc, Bothell, WA, USA) can assist nasogastric tube placement and PLMA insertion, but is difficult to use in patients with limited mouth opening [6]. The use of neuromuscular blocking agents to facilitate PLMA insertion is controversial in ankylosing spondylitis patients because of the presence of altered airway anatomy and restricted pulmonary function [7], although their use has been described [8]. We conclude that fibreoptic bronchoscopy allowed proper positioning of a ProSeal laryngeal mask airway after failure of normal blind techniques in a patient with severe ankylosing spondylitis. P.-C. Chiu K.-I. Cheng K.-Y. Tseng C.-K. Shih M.-K. Chen Kaohsiung Medical University Hospital, Kaohsiung, Taiwan Email: kuaich@kmu.edu.tw